[camera_android] Fix Android lint warnings (#3716)

Removes the lint-baseline.xml file, and fixes all issues.

The `KotlinPropertyAccess` doesn't seem to work well with generics. For example,

```java
class CameraFeature<T> {
  T getValue();
}

class ExposureFeature extends CameraFeature<Exposure> {
  @OverRide
  Exposure getValue() {
    ...
  }
}
```

The `ExposureFeature.getValue` causes the lint warning. I went ahead and suppressed this for all `CameraFeatures`.

I also added `@Nonnull` or `@Nullable` to some private fields that weren't required. This helped deduce whether a value was always nonnull or not.

Part of flutter/flutter#88011

Author: bparrishMines

packages/camera/camera_android/CHANGELOG.md

@@ -1,6 +1,11 @@
+## 0.10.6
+
+* Fixes Java warnings.
+
 ## 0.10.5
 
 * Allows camera to be switched while video recording.
+
 ## 0.10.4+3
 
 * Clarifies explanation of endorsement in README.

packages/camera/camera_android/android/build.gradle

@@ -38,7 +38,6 @@ android {
         checkAllWarnings true
         warningsAsErrors true
         disable 'AndroidGradlePluginVersion', 'InvalidPackage', 'GradleDependency'
-        baseline file("lint-baseline.xml")
     }
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8

packages/camera/camera_android/android/lint-baseline.xml

@@ -96,7 +96,7 @@ class Camera
    * Holds all of the camera features/settings and will be used to update the request builder when
    * one changes.
    */
-  private CameraFeatures cameraFeatures;
+  CameraFeatures cameraFeatures;
 
   private String imageFormatGroup;
 
@@ -116,28 +116,28 @@ class Camera
   private final ResolutionPreset resolutionPreset;
   private final boolean enableAudio;
   private final Context applicationContext;
-  private final DartMessenger dartMessenger;
+  final DartMessenger dartMessenger;
   private CameraProperties cameraProperties;
   private final CameraFeatureFactory cameraFeatureFactory;
   private final Activity activity;
   /** A {@link CameraCaptureSession.CaptureCallback} that handles events related to JPEG capture. */
   private final CameraCaptureCallback cameraCaptureCallback;
   /** A {@link Handler} for running tasks in the background. */
-  private Handler backgroundHandler;
+  Handler backgroundHandler;
 
   /** An additional thread for running tasks that shouldn't block the UI. */
   private HandlerThread backgroundHandlerThread;
 
-  private CameraDeviceWrapper cameraDevice;
-  private CameraCaptureSession captureSession;
+  CameraDeviceWrapper cameraDevice;
+  CameraCaptureSession captureSession;
   private ImageReader pictureImageReader;
-  private ImageReader imageStreamReader;
+  ImageReader imageStreamReader;
   /** {@link CaptureRequest.Builder} for the camera preview */
-  private CaptureRequest.Builder previewRequestBuilder;
+  CaptureRequest.Builder previewRequestBuilder;
 
   private MediaRecorder mediaRecorder;
   /** True when recording video. */
-  private boolean recordingVideo;
+  boolean recordingVideo;
   /** True when the preview is paused. */
   private boolean pausedPreview;
 
@@ -148,13 +148,13 @@ class Camera
   /** Holds the last known capture properties */
   private CameraCaptureProperties captureProps;
 
-  private MethodChannel.Result flutterResult;
+  MethodChannel.Result flutterResult;
 
   /** A CameraDeviceWrapper implementation that forwards calls to a CameraDevice. */
   private class DefaultCameraDeviceWrapper implements CameraDeviceWrapper {
     private final CameraDevice cameraDevice;
 
-    private DefaultCameraDeviceWrapper(CameraDevice cameraDevice) {
+    DefaultCameraDeviceWrapper(CameraDevice cameraDevice) {
       this.cameraDevice = cameraDevice;
     }
 
@@ -171,7 +171,6 @@ public void createCaptureSession(SessionConfiguration config) throws CameraAcces
       cameraDevice.createCaptureSession(config);
     }
 
-    @TargetApi(VERSION_CODES.LOLLIPOP)
     @SuppressWarnings("deprecation")
     @Override
     public void createCaptureSession(
@@ -235,9 +234,11 @@ public void onPrecapture() {
    *
    * @param requestBuilder request builder to update.
    */
-  private void updateBuilderSettings(CaptureRequest.Builder requestBuilder) {
+  void updateBuilderSettings(CaptureRequest.Builder requestBuilder) {
     for (CameraFeature<?> feature : cameraFeatures.getAllFeatures()) {
-      Log.d(TAG, "Updating builder with feature: " + feature.getDebugName());
+      if (BuildConfig.DEBUG) {
+        Log.d(TAG, "Updating builder with feature: " + feature.getDebugName());
+      }
       feature.updateBuilder(requestBuilder);
     }
   }
@@ -331,7 +332,9 @@ public void onOpened(@NonNull CameraDevice device) {
                     cameraFeatures.getFocusPoint().checkIsSupported());
 
             } catch (Exception e) {
-              Log.i(TAG, "open | onOpened error: " + e.getMessage());
+              if (BuildConfig.DEBUG) {
+                Log.i(TAG, "open | onOpened error: " + e.getMessage());
+              }
               dartMessenger.sendCameraErrorEvent(e.getMessage());
               close();
             }
@@ -489,7 +492,6 @@ private void createCaptureSessionWithSessionConfig(
             callback));
   }
 
-  @TargetApi(VERSION_CODES.LOLLIPOP)
   @SuppressWarnings("deprecation")
   private void createCaptureSession(
       List<Surface> surfaces, CameraCaptureSession.StateCallback callback)
@@ -498,7 +500,7 @@ private void createCaptureSession(
   }
 
   // Send a repeating request to refresh  capture session.
-  private void refreshPreviewCaptureSession(
+  void refreshPreviewCaptureSession(
       @Nullable Runnable onSuccessCallback, @NonNull ErrorCallback onErrorCallback) {
     Log.i(TAG, "refreshPreviewCaptureSession");
 
@@ -722,7 +724,7 @@ private void lockAutoFocus() {
   }
 
   /** Cancel and reset auto focus state and refresh the preview session. */
-  private void unlockAutoFocus() {
+  void unlockAutoFocus() {
     Log.i(TAG, "unlockAutoFocus");
     if (captureSession == null) {
       Log.i(TAG, "[unlockAutoFocus] captureSession null, returning");
@@ -1194,7 +1196,7 @@ public void onCancel(Object o) {
         });
   }
 
-  private void setImageStreamImageAvailableListener(final EventChannel.EventSink imageStreamSink) {
+  void setImageStreamImageAvailableListener(final EventChannel.EventSink imageStreamSink) {
     imageStreamReader.setOnImageAvailableListener(
         reader -> {
           Image img = reader.acquireNextImage();
@@ -1234,7 +1236,7 @@ private void setImageStreamImageAvailableListener(final EventChannel.EventSink i
         backgroundHandler);
   }
 
-  private void closeCaptureSession() {
+  void closeCaptureSession() {
     if (captureSession != null) {
       Log.i(TAG, "closeCaptureSession");
 

packages/camera/camera_android/android/src/main/java/io/flutter/plugins/camera/Camera.java

@@ -5,7 +5,6 @@
 package io.flutter.plugins.camera;
 
 import android.app.Activity;
-import android.os.Build;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import io.flutter.embedding.engine.plugins.FlutterPlugin;
@@ -45,7 +44,8 @@ public CameraPlugin() {}
    * won't react to changes in activity or context, unlike {@link CameraPlugin}.
    */
   @SuppressWarnings("deprecation")
-  public static void registerWith(io.flutter.plugin.common.PluginRegistry.Registrar registrar) {
+  public static void registerWith(
+      @NonNull io.flutter.plugin.common.PluginRegistry.Registrar registrar) {
     CameraPlugin plugin = new CameraPlugin();
     plugin.maybeStartListening(
         registrar.activity(),
@@ -97,11 +97,6 @@ private void maybeStartListening(
       BinaryMessenger messenger,
       PermissionsRegistry permissionsRegistry,
       TextureRegistry textureRegistry) {
-    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
-      // If the sdk is less than 21 (min sdk for Camera2) we don't register the plugin.
-      return;
-    }
-
     methodCallHandler =
         new MethodCallHandlerImpl(
             activity, messenger, new CameraPermissions(), permissionsRegistry, textureRegistry);

packages/camera/camera_android/android/src/main/java/io/flutter/plugins/camera/CameraPlugin.java

@@ -8,6 +8,8 @@
 import android.os.Build.VERSION_CODES;
 import android.util.Range;
 import android.util.Size;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 
 /** An interface allowing access to the different characteristics of the device's camera. */
@@ -18,6 +20,7 @@ public interface CameraProperties {
    *
    * @return String The name of the camera device.
    */
+  @NonNull
   String getCameraName();
 
   /**
@@ -30,6 +33,7 @@ public interface CameraProperties {
    * @return android.util.Range<Integer>[] List of frame rate ranges supported by this camera
    *     device.
    */
+  @NonNull
   Range<Integer>[] getControlAutoExposureAvailableTargetFpsRanges();
 
   /**
@@ -43,6 +47,7 @@ public interface CameraProperties {
    * @return android.util.Range<Integer> Maximum and minimum exposure compensation supported by this
    *     camera device.
    */
+  @NonNull
   Range<Integer> getControlAutoExposureCompensationRange();
 
   /**
@@ -64,6 +69,7 @@ public interface CameraProperties {
    *
    * @return int[] List of auto-focus modes supported by this camera device.
    */
+  @NonNull
   int[] getControlAutoFocusAvailableModes();
 
   /**
@@ -75,6 +81,7 @@ public interface CameraProperties {
    * @return Integer Maximum number of metering regions that can be used by the auto-exposure
    *     routine.
    */
+  @NonNull
   Integer getControlMaxRegionsAutoExposure();
 
   /**
@@ -85,6 +92,7 @@ public interface CameraProperties {
    *
    * @return Integer Maximum number of metering regions that can be used by the auto-focus routine.
    */
+  @NonNull
   Integer getControlMaxRegionsAutoFocus();
 
   /**
@@ -97,6 +105,7 @@ public interface CameraProperties {
    * @return int[] List of distortion correction modes supported by this camera device.
    */
   @RequiresApi(api = VERSION_CODES.P)
+  @Nullable
   int[] getDistortionCorrectionAvailableModes();
 
   /**
@@ -107,6 +116,7 @@ public interface CameraProperties {
    *
    * @return Boolean Whether this camera device has a flash unit.
    */
+  @NonNull
   Boolean getFlashInfoAvailable();
 
   /**
@@ -136,6 +146,7 @@ public interface CameraProperties {
    * @return Float Shortest distance from front most surface of the lens that can be brought into
    *     sharp focus.
    */
+  @Nullable
   Float getLensInfoMinimumFocusDistance();
 
   /**
@@ -148,6 +159,7 @@ public interface CameraProperties {
    * @return Float Maximum ratio between both active area width and crop region width, and active
    *     area height and crop region height.
    */
+  @NonNull
   Float getScalerAvailableMaxDigitalZoom();
 
   /**
@@ -159,6 +171,7 @@ public interface CameraProperties {
    *
    * @return Float Minimum ratio between the default zoom ratio and the minimum possible zoom.
    */
+  @Nullable
   @RequiresApi(api = VERSION_CODES.R)
   Float getScalerMinZoomRatio();
 
@@ -171,6 +184,7 @@ public interface CameraProperties {
    *
    * @return Float Maximum ratio between the default zoom ratio and the maximum possible zoom.
    */
+  @Nullable
   @RequiresApi(api = VERSION_CODES.R)
   Float getScalerMaxZoomRatio();
 
@@ -184,6 +198,7 @@ public interface CameraProperties {
    * @return android.graphics.Rect area of the image sensor which corresponds to active pixels after
    *     any geometric distortion correction has been applied.
    */
+  @NonNull
   Rect getSensorInfoActiveArraySize();
 
   /**
@@ -195,6 +210,7 @@ public interface CameraProperties {
    * @return android.util.Size Dimensions of the full pixel array, possibly including black
    *     calibration pixels.
    */
+  @NonNull
   Size getSensorInfoPixelArraySize();
 
   /**
@@ -209,6 +225,7 @@ public interface CameraProperties {
    *     to the application of any geometric distortion correction.
    */
   @RequiresApi(api = VERSION_CODES.M)
+  @NonNull
   Rect getSensorInfoPreCorrectionActiveArraySize();
 
   /**
@@ -254,5 +271,6 @@ public interface CameraProperties {
    *
    * @return int[] List of noise reduction modes that are supported by this camera device.
    */
+  @NonNull
   int[] getAvailableNoiseReductionModes();
 }